[Reactivity and evolution of 4022 patch tests in Chilean patients with contact dermatitis].

Background: Allergic Contact Dermatitis is a classic delayed hypersensitivity reaction.

Aim: To study the reactivity and evolution in Chilean patients by gender, using the standard European patch test.

Materials And Methods: The results of the European standard patch test applied to 4,022 patients aged 1 to 93 years (64% female) with Allergic Contact Dermatitis, diagnosed between January 1995 and August 2011, were retrospectively analyzed.

Results: From a total of 4,022 patients, 2,439 (60.6%) had a positive reaction. Among reactive patients, 1,854 (76.04%) were female and 584 (23.96%) male. The most common positive allergens were nickel (35.3%), cobalt (15.1%), fragrance mix (14%), chromium (8.7%) and balsam of Peru (8.5%). In females, nickel was the most common reactive antigen (34.28%), and in males, fragrance mix (15.7%). During the period 2003-2011, an increased reactivity to nickel (26.6%) and a decreased reactivity to p-phenylenediamine (29.6%) and fragrance (42.8%), was observed.

Conclusions: Fragrance mix is the most common reactive allergen in males and the third for females. Nickel is the leading allergen in the female group and the second of importance for males, making it the most significant allergen for the Chilean population. We also observed that the reactivity of some allergens evolves and varies over time.